Why does clang still need libgcc.a to compile my code?

Question

int main(int argc, char **argv)
{
    return 0;
}

I cross compile (host= linux x86_64, target= linux aarch64)

/path/to/clang --target=aar

Answer 1

You must compile with the option -nodefaultlib or -nostdlibs.

Here a quote from GCC documentation (clang interface is just the same):

One of the standard libraries bypassed by -nostdlib and -nodefaultlibs is libgcc.a, a library of internal subroutines which GCC uses to overcome shortcomings of particular machines, or special needs for some languages.

You may have to execute c++ static initialization routines and/or use what is provided by the object files crt.o in the lib directory. These files are part of libc and provides executable entry point.